gdb's built-in recording slows down the debuggee by about 1000x, rr more like 2x. That makes a huge difference in practice. rr's recording works across system

gdb's built-in recording slows down the debuggee by about 1000x, rr more like 2x. That makes a huge difference in practice. rr's recording works across system calls, thread context switches, etc, but gdb's doesn't. rr's recording creates a persistent recording on disk that you can even move around between machines. This permits workflows that gdb's doesn't. (Disclaimer: I work on rr)